I wonder if this is the song you have in mind, Jim -- a Candian tune historically mixed in with Silver Dagger but of different tune and lineage.

Who is at my window weeping,
Weeping there so bitterly?
"It's I, it's I, your own true loved one
Arise, arise and pity me."

"Darling, go and ask your mother
If thou my wedding bride will be
If she says no, return and tell me.
No longer will I trouble thee."

"How can I go and ask my mother
For I'm her only child and dear?
Oh, darling, go and seek some other,"
She softly whispered in his ear.

"Darling, go and ask your father
If thou my wedding bride will be
If he says no, return and tell me.
No longer will I trouble thee."

"My father's on his bed a-sleeping
With a shining sword placed on his breast
All for to slay my own true loved one,
To slay the lad that I love best."

Then William took the shining sword
And pierced it through his aching heart
"Adieu, adieu to all false loved ones.
Adieu, adieu, we both shall part."

Then Mary took the blood-stained sword
And pierced it through her lily white breast.
"Adieu, adieu to my cruel parents.
Adieu, adieu, we both shall rest."